WO2002103453A1

WO2002103453A1 - Image display screen and image display unit

Info

Publication number: WO2002103453A1
Application number: PCT/JP2002/006002
Authority: WO
Inventors: Taro Oya; Tadashi Shingu
Original assignee: Teijin Limited
Priority date: 2001-06-19
Filing date: 2002-06-17
Publication date: 2002-12-27
Also published as: EP1398660A4; US20040004760A1; US7031058B2; JP2003075920A; KR100893841B1; EP1398660B1; DE60232146D1; KR20030031164A; TW567389B; EP1398660A1

Abstract

An image display screen which is a multilayer film formed by alternately laminating in at least 11 layers a first thermoplastic resin layer (first layer) 0.05-03 μm in thickness and a second thermoplastic resin layer (second layer) 0.05-03 μm in thickness and having a parallel beam transmittance of at least 50%, and which has, on a reflectance curve with respect to a visible light with a wavelength of 380-780 nm, at least one reflection peak having a maximum reflectance 5-80% higher than the base line of a reflectance and a half width ranging from 20 to 200 nm; and an image display unit using the screen as an image display surface. The screen is characterized by being enhanced in transparency with the sharpness of an image retained.

Description

Image display screen and image display device

The present invention relates to an image display screen and an image display device. More specifically, a transparent image display screen that reflects an image on both the incident side and the transmission side of visible light by reflecting at least a part of the visible light emitted from the projector and a transparent image display screen using the same. The present invention relates to an image display device.

Conventional technology

In general, large-screen images are projected by a projector such as a liquid crystal projector. Then, in order to impart further design properties to the image projected by the projector 1, a transparent base material such as glass is used as an image display surface. The image projected on the transparent base material shows the other side of the image display surface, and expresses a new design.

As a method of displaying an image on such a transparent substrate, irregularities for irregularly reflecting light may be provided on the surface of the transparent substrate, or as disclosed in JP-A-2000-122181. Generally, a translucent so-called hologram screen is used. However, in the former method, the transparency of the image display surface must be reduced in order to clearly display the image, and the sharpness of the displayed image and the design are in conflict with each other. there were. In addition, the latter method requires the use of a very special polymer, and can increase the transparency while maintaining the sharpness of the image.However, the design obtained is the same as that of the former method. It was nothing but the same thing. The latter method can display the image on the transmission side more clearly than the former method, but cannot display the image on the reflection side clearly.

Disclosure of the invention

An object of the present invention is to solve the above-mentioned problems and to provide an image display screen which has improved transparency while maintaining sharpness of an image. Another object of the present invention is to provide a screen that reflects light emitted from a projector as a screen that reflects light interference between eyebrows, which is completely different from the conventional method using diffused light, to achieve sharpness of images. It is an object of the present invention to provide an image display screen that has improved transparency while maintaining the image quality.

Still another object of the present invention is to provide a film for the image display screen of the present invention.

Still another object of the present invention is to provide an image display device using the image display screen of the present invention.

Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and points of the present invention are, firstly,

(1) The first thermoplastic resin layer having a thickness in the range of 0.05 to 0.3 and the second thermoplastic resin layer having a thickness in the range of 0.05 to 0.3 m are alternately laminated. Consists of a multilayer film consisting of at least 11 layers,

(2) In a reflection curve for visible light having a wavelength of 380 to 780 nm, a reflection peak having a maximum reflectance of 5 to 80% higher than the baseline of the reflectance and a half width in the range of 20 to 200 nm, and

(3) The parallel light transmittance is 50% or more,

This is achieved by an image display screen characterized in that:

According to the present invention, the above objects and advantages of the present invention are:

(1) The first thermoplastic resin layer whose thickness is in the range of 0.05 to 0.3 m and the second thermoplastic resin layer whose thickness is in the range of 0.05 to 0.3 are alternately laminated. Made up of at least 11 layers,

(2) In a reflection curve for visible light having a wavelength of 380 to 780 nm, a reflection peak having a maximum reflectance of 5 to 80% higher than the baseline of the reflectance and a half-value width in a range of 20 to 200 nm,

(3) The parallel light transmittance is 50% or more, and

(4) For image display screen,

This is achieved by a multilayer film characterized in that: Further, according to the present invention, the above objects and advantages of the present invention are:

This is achieved by an image display device comprising a combination of the image display screen of the present invention and a projector that emits visible light having a wavelength of 380 to 780 nm.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an example of a graph of the reflectance with respect to the wavelength of light of the image display screen of the present invention.

FIG. 2 is another example of a graph of the reflectance with respect to the wavelength of light of the image display screen of the present invention.

FIG. 3 shows still another example of the Daraph of the reflectance of the image display screen of the present invention with respect to the wavelength of light.

FIG. 4 is still another example of a graph of the reflectance with respect to the wavelength of light of the image display screen of the present invention.

Embodiment of the Invention

The image display screen of the present invention includes a first thermoplastic resin layer (hereinafter, referred to as a first layer) and a second thermoplastic resin layer having a different composition from the thermoplastic resin constituting the first thermoplastic resin layer. This is a film in which thermoplastic resin layers (hereinafter, referred to as second layers) are alternately laminated. The thickness of each of the first layer and the second layer in the range of 0.05 to 0.3 nm is necessary for selectively reflecting light due to light interference between the layers. . The preferred thickness of each of the first layer and the second layer is in the range of 0.06 to 0.25 m. Further, the variation in the thickness of each of the first layer and the second layer is preferably at most 0.15 in relative standard deviation. When the relative standard deviation exceeds 0.15, the peak of the reflected light becomes broad, and it is difficult to obtain a clear hue. Note that the relative standard deviation of the thickness of the first layer (or the second layer) is obtained from the following equation.

Where ti is the thickness (m) of each layer of the first layer (or the second layer) t: Average value of the thickness of each one layer of the first layer (or the second layer) (m) 11: Number of layers of the first layer (or the second layer)

In the image display screen of the present invention, the first layer and the second layer are alternately stacked in at least 11 layers. When the number of layers is less than 10, the reflection of a specific wavelength due to light interference is not sufficient, and it is difficult to obtain sufficient visibility of a projected image to be used as an image display surface. A preferred lower limit of the number of layers of the first layer and the second layer is 31 or more, particularly 51 or more. The upper limit of the number of layers of the first layer and the second layer is not particularly limited. However, since the production process is not excessively complicated, the number of layers is preferably 501 or less, particularly preferably 301 or less.

The image display screen of the present invention has a parallel light transmittance of 50% or more. Here, the parallel light transmittance is a value measured based on a method defined by JIS K6714-1958, and means a ratio of light transmitted straight through a film. If the parallel light transmittance is less than 50%, an opaque image display surface is obtained, and the intended design cannot be obtained. The preferred parallel light transmittance is at least 60%, particularly preferably at least 75%.

In the image display screen of the present invention, it is necessary that the reflectance curve for each wavelength when a wavelength of 380 to 78 Onm is irradiated has a reflection peak having a specific shape. Specifically, the maximum reflectance at the peak of the reflection peak is in the range of 5 to 80% higher than the reflectance of the base line of the reflectance curve, and the half width is in the range of 20 to 20 Onm. It is necessary to have at least one reflection peak at Note that, for convenience of explanation, (maximum reflectance minus reflectance at the baseline) is hereinafter referred to as a reflection peak height. In addition, the half width here means the wavelength range of the outline from the long wavelength side to the short wavelength side of the reflection peak in the reflectance located at the midpoint between the maximum reflectance and the baseline reflectance. If there is no reflection peak with a reflection peak height of 5 to 80% and a half width of 20 to 200 nm in the visible light region with a wavelength of 380 to 780 nm, the reflection side of the target image display surface An image with excellent color cannot be projected on the transmission side with good visibility. Specifically, if the reflection peak height is less than 5%, the difference in hue between the transmission side and the reflection side becomes unclear, while if it exceeds 80%, the film itself becomes colored. It is clearly colored even when not projected. If the half-value width is less than 200 nm, visible light of a specific wavelength cannot be reflected sufficiently, so that only an image with poor visibility can be displayed. Since it reflects even visible light, high-contrast images cannot be projected on both the transmission side and the reflection side image display surfaces. The preferred height of the reflection peak is 15% to 60%, and the half width of the preferred reflection peak is in the range of 30 to: L50 nm, particularly 50 to L0 nm.

1 to 4 of the accompanying drawings are examples of the reflectance curves of the screen of the present invention. FIG. 1 is a reflectance curve of the screen reflecting blue light of the present invention. FIG. 2 is a reflectance curve of the screen reflecting green light of the present invention. FIG. 3 is a reflectance curve of the screen reflecting red light of the present invention. FIG. 4 shows a reflectance curve of a screen that reflects blue light, green light and red light of the present invention. In Figs. 1 to 4, 1 indicates the height of the reflection peak, 2 indicates the half width, and 3 indicates the baseline.

The image display screen of the present invention may be formed by further laminating another layer on one or both sides for the purpose of adjusting the overall thickness or providing other functions within a range where the optical characteristics are not deteriorated. Good. The term "other layer" as used herein includes a transparent polyester film, an antireflection layer, a metal thin film and a hard coat layer. Is also good.

In general, a projector that emits visible light emits visible light of three primary colors of light, R (red), G (green), and B (blue), when projecting an image. The wavelengths of these visible rays are 450 nm for R (red), 550 nm for G (green), and 620 nm for Β (blue). Therefore, in order to display an image using such a projector that irradiates the three primary colors of light, the image display screen of the present invention requires a wavelength of 420 to 480 nm and a wavelength of 520 to 58 It is preferable that a wavelength having a maximum reflectance exists in any of the ranges of 0 nm and 590 to 65 nm, and a reflection peak has a reflection peak height of 5% to 70%. The half width of the reflection peak is preferably in the range of 20 to 200 nm. It should be noted that even one of the reflection peaks can provide a reflection color or a transmission color and achieve sufficient visibility to be used as an image display surface. It is preferable to use one having a plurality of reflection peaks because it can express color. In particular, in any of the wavelength ranges of 420 to 480 nm, 52 to 580 nm, and 590 to 650 nm, the wavelength of maximum reflectance exists and the reflection peak height is high. Preferably, it has a reflection peak of 5% to 70%. In order to provide the image display screen of the present invention with a plurality of reflection peaks, two or more image display screens of the present invention having different reflection peaks may be bonded together, and the thickness of each layer of the image display screen of the present invention may be changed. You may. When a plurality of lights are reflected as described above, the half width of the reflection peak is preferably in the range of 20 to 100 nm. If the half width of the reflection peak is less than 20 nm, the reflection of the primary colors (red, green or blue) is insufficient, and it is difficult to obtain a reflected image with high visibility. On the other hand, if it exceeds 100 nm, the primary colors (red , Green or blue), the colors are mixed because they are reflected, and it is difficult to obtain a high-contrast image.

Such optical characteristics are caused by a difference in the refractive index between the first layer and the second layer. In the present invention, for convenience of explanation, a layer having a high refractive index is replaced with a layer having a low refractive index. Hereinafter, the layer may be referred to as a second layer. That is, in the image display screen of the present invention, the refractive index of the first layer is preferably larger than that of the second layer in at least one direction along the surface of the screen. Such a difference in refractive index is caused by using thermoplastic resins having different refractive indexes for the first layer and the second layer, or using thermoplastic resins having the same refractive index for the first layer and the second layer. It can be obtained by giving a difference in the refractive index in at least one direction along the film surface depending on the stretching conditions, or by using both methods together. Preferred refractive index differences range from 0.02 to 0.10 in at least one direction along the plane of the screen. When the refractive index difference is smaller than 0.02, the reflectance is reduced, and it is difficult to obtain sufficient visibility of a projected image for use as an image display screen. When the refractive index difference exceeds 0.10, the reflection is too strong, and the transparency of the image display surface is impaired, and the visibility of the image projected on the transmission side is impaired. More preferably, the difference in the refractive index in at least one direction along the film plane between the first layer and the second layer is from 0.03 to 0.90, particularly preferably from 0.04 to 0.90. 80.

In the case of a screen using a different resin, the reflection wavelength varies depending on the incident angle of the light beam because the reflection wavelength varies depending on the optical path length. Then, of such a ray To suppress the shift of the reflection wavelength due to the incident angle, use a polyester with a positive refractive index anisotropy as the thermoplastic resin constituting the first layer or the second layer, and stretch the film surface by stretching. It is preferable that at least one refractive index in the along direction is larger than the refractive index in the thickness direction. Particularly preferred is at least one of the first and second layers, and in particular both layers, wherein at least one refractive index in the direction along the film plane is less than the refractive index in the thickness direction. . 10 or more. By satisfying such a refractive index, the dependence on the incident angle of the light beam is reduced. Particularly preferred polyester is the main repeating unit due to its mechanical properties and film formation.

(Preferably 80 mol% or more) is occupied by ethylene terephthalate and ethylene-1,2,6-naphthalenedicarboxylate. By the way, compared to ethylene terephthalate, polyesters containing ethylene-1,2,6-naphthylene dicarboxylate as the main repeating unit exhibit a relatively high refractive index, so that the first layer has a higher refractive index than the second layer. It is also preferred that most of the repeating units are occupied by ethylene-1,2,6-naphthalenedicarboxylate, and that the second layer has a higher proportion of ethylene terephthalate than the first layer. preferable.

Next, the first layer and the second layer in the image display screen of the present invention will be described in detail below.

The thermoplastic resin constituting the first layer and the second layer is not particularly limited as long as it is transparent, and can be arbitrarily employed such as polyester, polyamide, polyacryl, and polystyrene. Among these, polyester is preferable for the above-mentioned reason, and particularly, ethylene rephthalate (hereinafter, sometimes referred to as ET) component or ethylene-1,2,6-naphthalenedicarboxylate (hereinafter, referred to as EN). Polyesters having a component as a main repeating unit are preferred. In particular, a polyester in which 80 mol% or more of the total repeating unit of the first layer and the second layer is an ET component or an EN component is preferable because the adhesion between layers is easily increased. When the ET component or the EN component is less than 80 mol% with respect to all the repeating units including the first layer and the second layer, the first layer and the second layer are formed. The composition of the polyester is greatly different, and the adhesion between the layers is poor, and the polyester may be peeled off. Polyester containing ET component or EN component as the main repeating unit, that is, polyethylene terephthalate (hereinafter sometimes referred to as PET) or polyethylene-1,2-naphthalenedicarboxylate (hereinafter referred to as PEN) Examples of the copolymerization component other than the ET component or EN component in) include terephthalic acid (only for PEN), isophthalic acid, 2,6-naphthalenedicarboxylic acid (only for PET), 2, Aromatic dicarboxylic acids such as 7-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and decane dicarboxylic acid; alicyclic dicarboxylic acids such as cyclohexic acid dicarboxylic acid; butanediol; Examples include aliphatic diols such as hexanediol and alicyclic diols such as heximimethanol.

By appropriately selecting the thermoplastic resin of each layer so that the refractive index of the first layer is larger than the refractive index of the second layer, the image display screen of the present invention can be used. Is obtained. Hereinafter, preferred combinations of thermoplastic resins will be described. Combination of thermoplastic resin of first layer and second layer (1)

As the thermoplastic resin constituting the first layer, PEN in which 95% by mole or more of all the repeating units are occupied by ethylene 1,2,6-naphthalenedicarboxylate is used, and the thermoplastic resin constituting the second layer is used. As the resin, 60 to 97 mol% of the total repeating units are occupied by ethylene-1,2,6-naphthylenedicarboxylate, and have a lower refractive index or melting point than PEN constituting the first layer. Low PEN. In this case, it is preferable to increase the amount of the copolymer component compared to the first layer in order to make the difference in the refractive index and the difference in the melting point. The means for increasing the amount of the copolymer component is not limited to a method using PEN with an increased amount of the copolymer component from the beginning.For example, a homo-PEN and a homo-PET are prepared and used in the film forming process. Transesterification by melt kneading to obtain a copolymer PEN having the desired composition may be used. Such a combination provides a high reflectance due to the use of PEN having a high refractive index as the first layer, and also has excellent adhesion between the layers due to the close composition of the two.

Combination of thermoplastic measurements of the first and second layers (2)

As the thermoplastic resin constituting the first layer, 95% by mole or more of all repeating units Adopt PET occupied by ethylene terephthalate, and as the thermoplastic resin constituting the second layer, 60 to 97 mol% of all repeating units are occupied by ethylene terephthalate and constitute the first layer The use of PET having a lower refractive index or a lower melting point than PET is mentioned. In this case, it is preferable to use more copolymer components than in the first layer in order to develop a difference in refractive index and difference in melting point. The means for increasing the amount of the copolymer component is not limited to a method using PET with an increased amount of the copolymer component from the beginning.For example, homo-PEN and homo-PET are prepared and melt-kneaded in the film forming process. May be used to form a copolymerized PET having a desired composition. Such a combination is easy to increase the reflectance because PET having a high refractive index is used as the first layer, and also has excellent adhesion between the layers due to the close composition of the two. Moreover, compared to PEN, the whitening phenomenon (delamination) that occurs when bending is less likely to occur, so that handling is excellent.

Combination of thermoplastic resin of first layer and second layer (3)

As the thermoplastic resin constituting the first layer, PET in which 85% by mole or more of the total repeating units is occupied by ET is used. As the thermoplastic resin constituting the second layer, 20 to 40% of the total repeating units is used. The use of PEN, which has a molar percentage of ET and 60 to 80 mol% of EN and has a lower refractive index or a lower melting point than the PET constituting the first layer, may be used. Also in this case, it is preferable to make the copolymer component more than that of the first layer in order to develop a difference in refractive index and difference in melting point. The means for increasing the amount of the copolymer component is not limited to the method using PET in which the amount of the copolymer component is increased from the beginning.For example, a homo-PEN and a homo-PET are prepared, and this is melted in the film forming process. It may be transesterified by kneading to obtain a copolymerized PET having a desired composition. By the way, when the method of giving the refractive index difference between the first layer and the second layer is based on the difference in melting point of the iT resin constituting each layer, the melting point of the thermoplastic resin constituting the second layer is 210 A copolymerized polyester having a melting point of 210 to 245 ° C is preferred, and a copolymerized PEN or PET having a melting point of 210 to 245 ° C is particularly preferred. If the melting point of the copolymerized polyester is less than 210 ° C., the crystallinity of the polymer becomes too low to form a film, and the heat resistance of the second layer may be excessively reduced. On the other hand, copolymerized poly If the melting point of the ester exceeds 245 ° C, oriented crystallization of the second layer tends to proceed when the first layer and the second layer are laminated and stretched, and a screen having a large difference in refractive index is required. It will be difficult to obtain. Further, it is preferable that the difference in melting point between the first layer and the second layer is at least 15 ° C. or more, because only the refractive index of the second layer can be selectively reduced by the heat setting treatment.

The melting point and T of the copolymerized polyester can be adjusted by appropriately selecting the types and amounts of the above-mentioned copolymerized components. Of these, isofluoric acid is preferred, and the copolymerization amount is preferably in the range of 4 to 18 mol%, more preferably 8 to 15 mol%. The intrinsic viscosity (orthochlorophenol, 35 ° C.) of the copolymerized polyester is preferably 0.45 to 0.8, more preferably 0.5 to 0.7.

Next, preferred embodiments of the image display screen of the present invention will be described in detail. At least one of the thermoplastic resins constituting the first layer and the second layer has an average particle diameter of preferably 0.01 to 5 ^ m, more preferably 0.1 to improve the winding property of the film. Inert particles in the range of from 01 to 2 m, more preferably from 0.05 to 1 m, particularly preferably from 0.1 to 0.3 m, preferably from 0.001 to 5% by weight, more preferably from 0.001 to 0.5% by weight. %, More preferably 0.005 to 0.2% by weight. If the average particle size of the inert particles is less than 0.01 m or the content is less than 0.001% by weight, the winding property of the film becomes insufficiently improved, while the average particle size of the inert particles exceeds 5 m Even if the particles are added or the content of the inert particles exceeds 5% by weight, the effect of improving the winding property is hardly obtained. Examples of the inert particles include inorganic inert particles such as silica, alumina, calcium carbonate, calcium phosphate, kaolin, and talc; and organic inert particles such as silicone, cross-linked polystyrene, and styrene-divinylbenzene copolymer. Can be mentioned. The inert particles may be spherical particles having a ratio of major axis to minor axis of preferably 1.2 or less, more preferably 1.1 or less (hereinafter, may be referred to as true spherical particles). This is desirable because it balances the slipperiness and optical properties of the material. Further, the inert particles preferably have a sharp particle size distribution, for example, the relative standard deviation is preferably less than 0.3, more preferably less than 0.2. New If particles with a large relative standard deviation are used, the frequency of coarse particles increases, which may cause optical defects.

Here, the average particle size, the particle size ratio, and the relative standard deviation of the inert particles were determined by first sprinkling a very thin metal on the particle surface to impart conductivity, and using an electron microscope to measure 10,000 to 30,000. From the magnified image, the major axis, minor axis, and area circle equivalent diameter are determined, and then calculated by applying the following equation.

Average particle size = Sum of equivalent circle diameters of measured particles / Number of measured particles

Particle size ratio = average major axis of particle Z average minor axis of the particle

As the inert particles, particles that act as pigments, such as titanium oxide and zinc sulfide, and particles that are colored deteriorate the optical characteristics. Therefore, it is preferable to avoid using such particles as much as possible. . It is particularly preferable that the above-mentioned inert particles are contained in the first layer and the second layer contains substantially no inert particles.

By the way, the inclusion of inert particles is preferable because the light selectively reflected by the screen is appropriately scattered, and the images on the projection side and the transmission side can be made clearer. If there are no inert particles in either the first layer or the second layer, almost all the light from the light source will be specularly reflected, making it difficult to see the displayed image depending on the angle, and the winding property of the screen. Is poor, and handling may be reduced.

Preferred inert particles from the viewpoint of visibility include, for example, inorganic inert particles such as silica, alumina, calcium carbonate, calcium phosphate, kaolin, and talc, silicone, cross-linked polystyrene, and styrene-divinylbenzene copolymer. Organic inactive particles. From the viewpoint of visibility, the average particle size of the inert particles is preferably 0.1 to 5 m, more preferably 0.3 to 3 m, and particularly preferably 1 to 3 m. Further, the content of the inactive particles, which is preferable from the viewpoint of visibility, is preferably from 0.01 to 0.5% by weight, more preferably from 0.1 to 0.5% by weight, based on the weight of the first layer or the second layer. It is in the range of 0.5-0.2% by weight. If the average particle size of the inert particles is less than the lower limit or the content is less than the lower limit, the obtained sharpness improving effect may be poor. On the other hand, if the average particle size of the inert particles exceeds the upper limit, Or, when the content exceeds the upper limit, deterioration of optical properties due to particles becomes remarkable, and the parallel light transmittance of the entire film tends to be less than 60%.

Subsequently, an example of a method for producing the screen of the present invention will be described.

In the production of the screen of the present invention, first, a laminated unstretched film is produced by a simultaneous multilayer extrusion method using a feed block. That is, a melt of a thermoplastic resin (for example, a mixture of PET containing inert particles) forming the first layer and a melt of a polymer (for example, copolymerized PET) forming the second layer are Using a feed block, two layers are laminated alternately so that the first layer is formed on both end layers, and are spread on a die and extruded. At this time, the polymer laminated by the feed block maintains the laminated form. The sheet extruded from the die is cooled and solidified by a casting drum to form a multilayer laminated unstretched film. Next, the unstretched multilayer laminated film is stretched in at least one direction, preferably biaxially, to form a screen. The stretching temperature at this time is preferably in the range of T g of the polymer of the first layer to T g + 50 ° C. The stretching ratio is preferably from 2 to 10 in the case of uniaxial stretching, and the stretching direction may be the film forming direction (in the present invention, sometimes referred to as the longitudinal direction or the machine direction). It may be a direction perpendicular to the film direction (in the present invention, it may be referred to as a lateral direction or a width direction). In the case of biaxial stretching, the stretching ratio in the machine direction and the transverse direction is preferably 1.2 times or more, more preferably 1.5 times or more, and the area magnification is, for example, 5 times to 25 times. If the stretching ratio is large, the thickness before stretching can be increased, and if the variation in the thickness of the layers in the multilayer laminated film before stretching is the same, the greater the stretching ratio, the smaller the thickness variation after stretching. As a result, light interference in each layer is expanded, and the reflectance can be increased, which is preferable. From such a point, the area magnification is preferably 8 times or more, and more preferably 10 times or more. As the stretching method, known stretching methods such as sequential biaxial stretching, simultaneous biaxial stretching, tubular stretching, and inflation stretching can be used. Of these, sequential biaxial stretching is preferred in terms of productivity and quality. The stretched film is preferably subjected to a heat treatment (heat setting treatment) for thermal stabilization. When the heat treatment temperature is based on the melting point (TmA) of the polymer of the first layer, (TmA—6 0) ° C ~ (TmA-10). In the case where the heat treatment selectively reduces the refractive index of the second layer, the melting point (TmB) of the polymer of the second layer is expressed as (TmB-1 The heat treatment is preferably performed in the range of 0) ° C to (TmA-10) ° C.

Incidentally, the above-mentioned screen may be provided with an adhesive layer (preferably a slippery adhesive layer) on at least one surface thereof. The purpose of the adhesive layer provided in this way is to provide a film with a slipperiness in addition to a hard coat layer formed thereon and an adhesive property to the pressure-sensitive adhesive layer, and to provide a film with a hard coat layer and an adhesive layer. Prevention of interfacial reflection with the surface can be achieved, and a known one may be selected.

In addition, the image projection screen of the present invention is preferably used as a transparent image display by sticking it to a transparent support such as glass for projecting with a liquid crystal projector or the like. At this time, in the image projection screen of the present invention, an adhesive layer is formed on both surfaces, an adhesive layer is laminated on one surface, a hard coat layer is laminated on the other surface, and the eighteenth layer is laminated. Is preferred. As in the above-mentioned adhesive layer, the hard coat layer and the pressure-sensitive adhesive layer may be appropriately selected from those known per se. Further, as described, the image display screen of the present invention can be formed by bonding a plurality of image display screens of the present invention having different reflection peaks or by changing the thickness of each layer of the image display screen of the present invention, It is preferable that the reflection peak has a multiple number. In particular, the present invention has a reflection peak in which the wavelength of the maximum reflectance exists in any of the wavelength ranges of 420 to 480 nm, 52 to 580 nm, and 590 to 65 nm. The image display screen can reflect all three primary colors of red, green and blue emitted from the projector, and can display a full-color image clearly.

The image display screen of the present invention thus obtained is, for example, attached to a transparent support such as glass as described above, and is applied to a liquid crystal projector or the like which emits light having a wavelength of 380 to 780 nm. By combining with a representative projector, it is possible to provide an image display device having an excellent visibility while having a novel design property that has never been seen before. Next, the present invention will be described with reference to examples. The physical properties in the examples were measured by the following methods.

(1) Parallel light transmittance and haze value

Measure the total light transmittance Tt (%) and the scattered light transmittance Td (して) using a haze meter (NDH-20) manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS K6714-1958. did. Here, the parallel light transmittance Tp (%) is obtained by the following equation.

T (p) = T (t) — T (d)

Haze (%) was calculated from the following equation from the measured total light transmittance Tt (%) and scattered light transmittance Td (%).

Haze (%) = T (d) ZT (t) X 100

(2) Refractive index in the direction along the film surface

Attach a polarizing plate analyzer to the eyepiece side of an Abbe refractometer (Abego Co., Ltd., Abbe refractometer 4 T), and use methylene sulfur iodide as the mounting solution and measure monochromatic light Na at a measurement temperature of ₂₅ . The machine direction refractive index (nx) and the width direction refractive index (ny) of the film were measured at line D. Regarding the refractive index in each direction, two boundary lines were confirmed in the sample, and the measured values were taken as the refractive index of the first layer and the refractive index of the second layer.

(3) Thickness of each layer (maximum thickness and minimum thickness)

Cut the sample into triangles, fix in an embedding capsule, and embed with epoxy resin. Then, the embedded sample was cut into a thin section of 5 Onm thickness in a section parallel to the longitudinal direction with a microtome (ULTR ACUT-S, manufactured by Reichert), and then a transmission electron microscope (JEM2010, manufactured by JEOL Ltd.) ) Was observed at an accelerating voltage of 10 O kv and photographed, and the thickness of each layer was measured from the photograph.

(4) Reflection peak height

Using a spectrophotometer UV-3101 manufactured by Shimadzu Corporation, the relative specular reflectance with the aluminum-deposited mirror at each wavelength is measured in the wavelength range of 380-780 nm. The largest of the measured reflectivities is the maximum reflection peak, and the height from the tail of the peak is the reflection peak height.

(5) Peak half width The same measurement as the maximum reflectance is performed. The peak half width was set.

(6) Melting point (Tm) and glass transition point (Tg)

A sample is sampled at 2 Omg, and the glass transition degree and the melting point are measured using a DSC (manufactured by TA Instruments, Inc., trade name: DSC 2920) at a heating rate of 20 ° C / min.

(7) Visibility of projected image

The sample was pasted on 1 Omm glass, and a liquid crystal projector projected red, green, blue, and full-color images. The projected images were observed from the reflection side and the transmission side under the fluorescent lamp lighting of 30 lux, and the visibility of the images was evaluated. ：: The hue contrast is high, and the image can be clearly seen.

〇: The hue cannot be confirmed clearly, but the projected characters can be read.

Δ: It can be confirmed that the image is displayed, but the content cannot be determined.

X: Cannot confirm whether the image is displayed.

(8) Transparency

The sample was affixed on a 1 Omm glass, and the visibility of the opposite scene was evaluated in three levels under fluorescent lighting of 30 lux.

3: You can clearly see the image on the other side without feeling cloudy at all.

2: The image on the opposite side can be seen, but lacks contrast and is slightly cloudy.

1: The image on the opposite side is not visible at all.

Example 1

Spherical silica particles (average particle diameter: 1.5 m, ratio of major axis to minor axis; 1.02, average deviation of particle diameter; 0.1) containing 0.1 Owt% (Polyol, 35 ° C) Polyethylene terephthalate (PET) of 0.63 was used as the resin for the first layer, and 1% of Ophthalmic acid was copolymerized with 1% of Ophthalmic acid. Tallate (intrinsic viscosity 0 · 68, orthochlorophenol, 35) was prepared as the resin for the second layer.

After drying the resin of the first layer at 160 ° C for 3 hours and the mixed resin of the second layer at 160 ° C for 3 hours, it is supplied to an extruder and melted, and the polymer of the first layer is polymerized. After the polymer of the 101st layer and the second layer is branched into the 100th layer, the stacking state is obtained by using a multilayer feedblock device in which the first layer and the second layer are alternately stacked. While holding the sheet, the sheet was guided to a die, and cast on a casting drum, to prepare a total of 201 layers of unstretched sheets in which the first layer and the second layer were alternately stacked. At this time, the extrusion amount of the second layer and the first layer was adjusted to be 1: 0.8, and the layers were laminated such that both end layers became the second layer. The laminated unstretched sheet is stretched 3.6 times in the machine direction at a temperature of 85, further stretched 3.9 times in the transverse direction at a stretching temperature of 9, and heat-set at 205 for 3 seconds. The image display screen was obtained.

The manufacturing conditions are shown in Table 1, the characteristics of the obtained image display screen are shown in Table 2, and the reflectance with respect to the wavelength of light is shown in FIG.

The obtained image display screen was attached to a 10-mm glass plate using an adhesive sheet (double-sided adhesive tape HJ-3160 W manufactured by Nitto Denko Corporation) to obtain a fluorescent light of 30 lux. When the LCD projector projects white light (red, green, and blue light) on a screen on a glass plate under lamp lighting, the image is blue-based from the reflective surface and yellow-based from the transmissive surface. Could be displayed with good contrast, and the transparency was very high. Table 3 shows the characteristics of the obtained image display surface.

Example 2

The same operation as in Example 1 was repeated, except that the manufacturing conditions were changed as shown in Table 1. Table 2 shows the characteristics of the obtained image display screen, and FIG. 2 shows the reflectance with respect to the wavelength of light.

Further, the obtained image display screen was attached to a 10 mm glass plate using the above-mentioned adhesive sheet, and white light (red, green, and green light) was irradiated with a liquid crystal projector under a fluorescent light of 30 lux. (Blue light) is projected onto a screen on a glass plate. From the reflective surface side, a blue tone image is displayed, and from the transmissive surface side, a purple tone image is displayed with good contrast. It was possible and the transparency was very high. Table 3 shows the characteristics of the obtained image display surface.

Example 3

The same operation as in Example 1 was repeated, except that the manufacturing conditions were changed as shown in Table 1. Table 2 shows the characteristics of the obtained image display screen, and Fig. 3 shows the reflectance with respect to the wavelength of light.

Also, the obtained image display screen was attached to a 10 mm glass plate using the above-mentioned adhesive sheet, and white light (red, green, and blue) was obtained with a liquid crystal projector under a fluorescent light of 30 lux. When the light was projected onto a screen on a glass plate, a red-based image could be displayed from the reflective surface side and a light blue-based image could be displayed from the transmissive surface side with good contrast, and the transparency was very high. Table 3 shows the characteristics of the obtained image display surface.

Examples 4 to 9

The same operation as in Example 1 was repeated, except that the resin and inert particles of the first layer and the second layer and the production conditions were changed as shown in Table 1. Table 2 shows the characteristics of the obtained image display screen. Table 3 shows the characteristics of the obtained image display surface. Example 10

Three image display screens manufactured in Examples 1 to 3 were stacked using an adhesive sheet, and attached to a glass plate having a thickness of 1 Omm using the adhesive sheet. When projected on a screen on a glass plate with a liquid crystal projector under a 30-lux fluorescent light, full-color images could be displayed with good contrast from either the reflective side or the transmissive side. Table 3 shows the characteristics of the obtained image display surface, and Fig. 4 shows the reflectance of the image display screen with respect to the wavelength of light.

Example 1 1

Three image display screens manufactured in Examples 7 to 9 were stacked using an adhesive sheet, and bonded to a glass plate having a thickness of 1 Omm using the adhesive sheet. When projected on a screen on a glass plate with a liquid crystal projector under a 30-lux fluorescent light, full-color images can be seen from both the reflective side and the transmissive side. Could be displayed well. Table 3 shows the characteristics of the obtained image display surface.

Comparative Example 1

A sticky film (TW-75) manufactured by Teijin Dupont Film Co., Ltd. is attached to a 10 mm glass plate using the above-mentioned adhesive sheet. When projected onto a film on a glass plate, the central image could be displayed with good contrast, but the image on the transmission side and the image on the reflection side had the same color tone, but there was no transparency at all. . Table 3 shows the characteristics of the image display surface.

Comparative Example 2

A hologram screen (Glass Vision Sheet 40) manufactured by Canon Inc. is attached to a 10 mm glass plate using the above-mentioned adhesive sheet, and the film on the glass plate is illuminated with a liquid crystal projector under a 30 lux fluorescent light. As a result, an image with very high contrast was displayed from the transmission side, but almost no image was seen from the reflection side. Transparency I was much more transparent than Comparative Example 1, but was slightly cloudy. Table 3 shows the characteristics of the image display surface.

11 layers

Fe fe U said kind of small evaluation in JJ)

-(t%) Example 1 101 H Α (0.05) 100 I None Example 2 101 HA (0.05) 100 I None Example 3 101 HA (0.05) 100 I None Example 4 101 J BC0.05) 100 K None Example 5 101 JB (0.05) 100 K None Example 6 101 JB (0.05) 100 K None Example 7 101 MC (0.05) 100 L None Example 8 101 MC (0.05) 100 L None Example 9 101 MC (0.05) 100 L None Manufacturing conditions Film thickness Longitudinal stretching Lateral stretching Heat setting temperature

Temperature (.C) Temperature (.C) Magnification (-) X μΐη Example 1 85 3.6 90 3.9 205 13

Example 2 85 3.6 90 3.9 205 16

85 3.6 90 3.9 205 18 Example 4 120 3.6 125 3.9 230 13

Example 5 120 3.6 125 3.9 230 16

Example 6 120 3.6 125 3.9 \ 230 18

Example 7 120 3.6 115 3.9 200 13

Example 8 120 3.6 115 3.9 200 16

Example 9 120 3.6 115 3.9 200 18

Table 2

t

Melting point peak before lamination by DSC Reflection wavelength Reflection peak height Half width

High temperature side Low temperature side

[° C] [. c] [Ml] [%] [nm]

Example 1 254 230 456 17 21

Example 2 254 230 546 14 23

Example 3 254 230 622 17 22

Example 4 265 240 445 51 38

Example 5 265 240 553 45 42

Example 6 265 240 621 44 43

Example 7 230 200 444 51 48

Example 8 230 200 561 45 53

Example 9 230 200 630 44 55

Table 3 ノし >> 飽ヽヽ Λ Λ Λ 視認視認 Image visibility (transmission side) Image visibility (reflection side)

Γ¾) 1 '' 1 ''

Example 1 on o XX o XX «« Example 2 86 81 6 X ◎ X 〇 X ◎ X 〇 3 Example 3 87 84 4 XX ◎ 〇 XX ◎ 〇 3 Example 4 89 85 4 ◎ XX 〇 ◎ XX 〇 3 Example 5 85 81 4 X ◎ X 〇 X ◎ X 〇 3 Example 6 87 83 4 XX ◎ 〇 XX ◎ 〇 3 Example 7 89 86 3 ◎ XX 〇 ◎ XX 〇 3 Example 8 78 74 4 X ◎ X 〇 X ◎ X 〇 3 Example 9 86 82 4 XX ◎ 〇 XX ◎ 〇 3 Example 10 78 60 18 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ 3 Example 11 64 54 10 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ 3 Comparative Example 1 60 18 70 〇〇〇〇〇〇〇〇 1 Comparative Example 2 65 40 38 ◎ ◎ ◎ ◎ XXXX 2

The inert particles shown in Table 1 are as follows.

Inert particles A: true spherical silica particles (average particle diameter: 1.5 m, ratio of major axis to minor axis; 1.02, average deviation of particle diameter; 0.1)

Inert particles B: lumpy calcium carbonate (Average particle size: 1. Οπι, ratio of major axis to minor axis; 1.4, average deviation of particle diameter; 0.25)

Inert particles C: spherical silicone (average particle size: 1.5 im, ratio of major axis to minor axis; 1.1, average deviation of particle diameter; 0.30)

The resin type of the first layer or the second layer shown in Table 1 is as follows.

Resin type H: Polyethylene terephthalate (Intrinsic viscosity 0.64, Orthochlorophenol, 35 ° C)

Resin type I: Copolymerized polyethylene terephthalate obtained by copolymerizing isophthalic acid with 1% Omo 1% (intrinsic viscosity 0.68, phenol phenol, 35)

Resin type J: Polyethylene 2,6-naphthalate (intrinsic viscosity 0.62, orthophenol phenol, 35 ° C)

Resin type K: Copolymerized polyethylene 2,6-naphthalate obtained by copolymerizing isophthalic acid with 1% Omo 1% (intrinsic viscosity 0.64, orthochlorophenol, 35) Resin type L: Polyethylene 2,6-naphthalate (intrinsic viscosity 0. A mixture of 62, orthochlorophenol, 35X) and polyethylene terephthalate (intrinsic viscosity 0.64, orthochlorophenol, 35) in a weight ratio of 70:30 Resin type M: 2,6-naphthalenedicarboxylic acid 12 mo 1% copolymerized poly (ethylene terephthalate) (intrinsic viscosity 0.68, phenol with an orthochrome, 35 ° C) The image display screen of the present invention is formed under the film forming conditions shown in Table 1. As shown in Table 2, it selectively reflects the wavelength without losing transparency. By pasting such a multilayer stretched film on glass, as shown in Table 3, images are not obtained in Comparative Examples 1 and 2, and images are displayed on both the transmission side and the reflection side while maintaining transparency. can do.

As described above, the image display screen of the present invention reflects at least a part of visible light within a range that does not lose transparency, and thus has high transparency while maintaining sharpness of the image. In addition, a new design that has never existed before, that is, images having different color tones can be simultaneously displayed on the reflection side and the transmission side. Therefore, when the screen of the present invention is pasted on, for example, a window glass of a store that is open late at night, and an image is displayed by a liquid crystal projector, it is possible to obtain image information while checking the outdoor scenery from indoors. You can check video information from outside from outside. Therefore, the use of the image display device of the present invention can reduce the discomfort given to the surrounding residents even when an advertisement or the like is displayed at midnight, and can carry out efficient advertising activities.

Claims

The scope of the claims

1. (1) The first thermoplastic resin layer having a thickness in the range of 0.05 to 0.3 m and the second thermoplastic resin layer having the thickness in the range of 0.05 to 0.3 m It consists of a multilayer film consisting of at least 11 layers alternately laminated,

(2) In the reflectance curve for visible light with a wavelength of 380 to 780 nm, the reflection peak whose maximum reflectance is 5 to 80% higher than the baseline of the reflectance and whose half width is in the range of 20 to 200 nm is found. Have and

(3) parallel light transmittance is 50% or more,

An image display screen, characterized in that:

2. The wavelength showing the maximum reflectance of the reflection peak is in the range of 420 to 480 nm, 520 to 580 nm, or 590 to 650 nm, and the maximum reflectance is higher than the reflectance baseline. The image display screen according to claim 1, which is in a range of 5 to 70% higher.

3. The image display screen according to claim 1, wherein at least one of the first thermoplastic appearance layer and the second thermoplastic resin layer contains inert particles.

4. The inert particles are selected from the group consisting of silica particles, alumina particles, calcium carbonate particles, calcium phosphate particles, kaolin particles, talc particles, silicone particles, crosslinked polystyrene particles, and styrene-vinylbenzene copolymer particles. 4. The image display screen according to claim 3, which is at least one kind.

5. The image display screen according to claim 4, wherein the inert particles have an average particle size in a range of 0.01 to 5 m.

6. The inert particles are present in the range of 0.001 to 5% by weight based on the weight of the multilayer film. 4. The image display screen according to claim 3, wherein the image display screen is enclosed in a box.

7. The method according to claim 1, wherein the first thermoplastic resin is a polyester mainly composed of ethylene-1,2,6-naphthyl propylene oxide or a polyester mainly composed of ethylene terephthalate. Image display screen.

8. The image display according to claim 1, wherein the second thermoplastic resin is a polyester having ethylene-2,6-naphthene dicarboxylate as a main repeating unit or a polyester having ethylene terephthalate as a main repeating unit. screen.

9. The image display screen according to claim 1, wherein the first thermoplastic resin and the second thermoplastic resin before being laminated on the multilayer film have a temperature difference of at least 15 in melting point by DSC.

2. The image display according to claim 1, wherein the thermoplastic resin (10.l) and the second thermoplastic resin are both polyester, and at least 80 mol% of all the repeating units of the polyester are composed of ethylene terephthalate. screen.

11. The first thermoplastic resin and the second thermoplastic resin are both polyesters, and at least 80 mol% of all repeating units of the polyester are ethylene-2,6-naphthalenedicarboxylate. The image display screen according to claim 1, wherein the image display screen comprises:

1 2. There are at least three reflection peaks, and the wavelengths showing the maximum reflectivity of the three reflection peaks are 420-480 nm, 520-580 nm, and 590-650, respectively. The image display screen according to claim 1, wherein the maximum reflectance of each of the three reflection peaks is in a range of 5 to 70% higher than a baseline of the reflectance.

13. The image display screen according to claim 1, which is bonded to a transparent support.

14. (1) The first thermoplastic resin layer whose thickness is in the range of 0.05 to 0.3 m and the second thermoplastic resin layer whose thickness is in the range of 0.05 to 0.3 m Consists of at least 11 layers that are alternately stacked,

(2) In the reflectance curve for visible light with a wavelength of 380 to 780 nm, the reflection peak where the maximum reflectance is 5 to 80% higher than the baseline of the reflectance and the half width is in the range of 20 to 200 nm. Have

(3) parallel light transmittance is 50% or more, and

(4) For image display screen,

A multilayer film characterized by the above-mentioned.

15. Use of the multilayer film according to claim 14 as an image display screen.

16. An image display device comprising a combination of the image display screen according to any one of claims 1 to 13 and a projector that emits visible light having a wavelength of 380 to 780 nm.